1. Field of the Invention
This invention relates to power generation and storage devices and is directed more particularly to a hybrid power assembly including a thermophotovoltaic power conversion module in combination with a battery rechargeable by the module.
2. Description of the Prior Art
The U.S. Army purchases large quantities of batteries to meet the needs of the dismounted soldier for both military missions and for training for such missions. For actual missions, the lower weight and higher stored energy of non-rechargeable batteries make them a clear choice. For training, rechargeable batteries are used more often because they can be recharged hundreds of times, thereby making their life-cycle costs much lower than that of non-rechargeable batteries. The higher weight and lower stored energy of rechargeable batteries, compared to non-rechargeable batteries, requires more rechargeable batteries and a correspondingly higher weight for the soldier to carry in training for a mission, than for the actual mission. The time required to recharge batteries is also problematic in a military environment.
A non-rechargeable battery used in large quantities by the Army is referred to as the BA-5590. This is a lithium-sulfur dioxide battery with a nominal output of 12 or 24 volts with a current flow capability of 4 or 2 amps, respectively, for approximately 3.4 hours. This represents a capacity of approximately 163 watt-hours. The overall battery dimensions are 4.4 inches wide, by 2.45 inches deep, by 5.0 inches high. This battery and its rechargeable alternative, the BB-390A/U, are useable in many military platforms, and represent a significant fraction of the cost of batteries purchased by the Army.
The performance characteristics of the batteries are presented below. While the batteries are identical in size and configuration, the weight of the rechargeable BB-390A/U battery is 65% higher than that of the non-rechargeable BA-5590 battery. The capacity of the rechargeable BB-390A/U is only 47% of the BA-5590 battery. It is because of such advantages, that non-rechargeable batteries usually are preferred for military missions.
BA-5590 Battery BB-390 A/U Battery Specifications Non-Rechargeable Rechargeable Dimensions (l .times. w .times. h), in 4.4 .times. 2.45 .times. 5.0 Same Volume, in.sup.3 53.9 Same Weight, lb 2.33 3.85 Max. Current, amps 4/2 7.2/3.6 Nominal Voltage, volts 12/24 Same Max. Power, watts 48 86 Storage Capacity, w-h 163 77
It is desired to provide a power source for the foot soldier which provides higher stored energy then electrochemical batteries, provides for greatly shortened recharging times, provides high instantaneous power, and is smaller in size and weight than the customarily used quantities of BA-5590 and BB-390A/U batteries. It is further desired that the power source be useable after being submerged in water, when disposed in any orientation, and when subjected to atmospheres having contaminants therein.